Question 1143482: James can jog twice as fast as he can walk. He was able to jog the first 9 miles to his grandmother’s house, but then he tired and walked the remaining 1.5 miles. If the total trip took 2 hours, then what was his average jogging speed?
Found 4 solutions by ankor@dixie-net.com, ikleyn, greenestamps, josgarithmetic:
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! James can jog twice as fast as he can walk.
He was able to jog the first 9 miles to his grandmother’s house, but then he tired and walked the remaining 1.5 miles.
If the total trip took 2 hours, then what was his average jogging speed?
:
let j = his jogging speed
he walks half as fast, therefore
.5j = his walking speed
:
write a time equation, time = dist/speed
jog time + walk time = 2 hrs
 +  = 2
multiply by .5j
.5(9) + (1.5) = .5j(2)
4.5 + .1.5 = j
6 = j
j = 6 mph is the jogging speed
:
:
Check, find the actual time of each
9/6 = 1.5 hrs
1.5/3 = .5 hrs
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total time 2 hrs
Answer by ikleyn(52943)  (Show Source):
Answer by greenestamps(13216)  (Show Source):
You can put this solution on YOUR website!
A solution using logical reasoning instead of formal algebra....
He walked for 1.5 miles at a rate half of his jogging speed.
If he had not tired and kept jogging instead, he could have covered 3 miles in the same amount of time.
So in the 2 hours it took for the whole trip he could have covered 9+3=12 miles if he had continued jogging.
That means his jogging speed is 12/2 = 6mph.
Answer by josgarithmetic(39632)  (Show Source):
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